Embodiments of the present invention relate generally to a communication system for medical applications and monitoring of equipment used in the care of monitored patients. More particularly, embodiments of the present invention assess the status of a patient using a rule applied by a rules engine and use patient data to evaluate the effectiveness of the rule and to determine whether the rule requires modification.
Advances in communications, video displays, monitoring devices and computers have made it possible to remotely monitor hundreds of monitored patients. Alerting systems may be deployed to alert healthcare providers when certain conditions are met. For example, in U.S. Pat. No. 5,942,986 issued to Shabot, et. al for a “System And Method For Automatic Critical Event Notification,” describes a critical event notification system that permits review of a patient's diagnostic information, lab results, chart, or other data, automatically, by computer or similar equipment, and it provides for automatic paging of a responsible physician or physicians should a “critical event” be detected. The decision to page an individual is made automatically by the system, and does not require a direct human decision.
“Decision Support Systems in Critical Care” (Edited by M. Michael Shabot and Reed M. Gardner, 1994), is a compilation of articles that collectively describe the application of computers in health care settings. Decision support systems are defined as systems that receive medical data as input and produce medical information and/or knowledge as output. In some implementations, decision support systems utilize inferencing methods to detect associations between different pieces of information, alerting clinicians to certain patterns of events, which may be serious or life-threatening.
An example implementation of an inferencing method is described in the context of analyzing blood gas readings and laboratory results. Three different types of alerting algorithms are described: 1) high and low critical values 2) calculation-adjusted critical values, and 3) critical trends. (See, Decision Support Systems in Critical Care, pages 157-65.) The calculation-adjusted critical value algorithm reflects the dependence of the algorithm on multiple parameters. The application of the inferencing module produces an alert that is displayed on a screen or sent to a wireless device.
In U.S. Pat. No. 6,804,656 issued to Applicants, a smart alarm system was described. The smart alarm system of the '656 Patent, constantly monitors physiologic data and all other clinical information stored in the database (labs, medications, etc). The rules engine searches for patterns of data indicative of clinical deterioration. By way of illustration, one family of alarms looks for changes in vital signs over time, using pre-configured thresholds. These thresholds (also referred to as “rules”) are patient-specific and setting/disease-specific. Physiologic alarms can be based on multiple variables. For example, one alarm looks for a simultaneous increase in heart rate of 25% and a decrease in blood pressure of 20%, occurring over a time interval of 2 hours. Alarms also track additional clinical data in the patient database. Other rules follow laboratory data (e.g. looking for need to exclude active bleeding and possibly to administer blood). Regardless of the data elements that are used, the purpose of the rules is to facilitate detection of changes in a patient's condition (whether that condition is improving or degrading) in a predictive manner and to automate a response appropriate to the “new” condition.
Establishing rules requires an understanding the relationship between changes in the variables tracked by the rule and adverse clinical events. Historical patient data may be used to establish an initial rule. However, it would be useful if a smart alarm system were able to update a rule based on the effectiveness of the previous rule.